The Democratic contest for the presidential nomination in 1960 was wide open, unlike 1956. Sens. Kennedy and Humphrey vied for the nomination through the primaries. Sens. Johnson and Symington worked through the caucus system, while Stevenson and Harriman waited in the wings in case the convention became deadlocked.

Background.
The first hard evidence that JFK's catholicism was an issue came in Wisconsin. While he defeated HHH by a 56-43% margin, the vote by congressional district was telling. Of the 10 districts, JFK won the five with Catholic majorities, lost all four with Protestant majorities, and barely won the one that was evenly divided. Humphrey sent his campaign staff to West Virginia, an overwhelmingly Protestant state, for a re-match.

Humphrey challenged JFK to a debate, which was accepted on 4/19/1960. This represented a change in JFK's strategy. In Wisconsin, he had declined to debate HHH, had carefully avoided attacking him, and did not respond to HHH's attacks. His strategy worked in Wisconsin because he had a large base to work with. [NYT 4/20/1960]

The campaigns agreed to hold the debate on 5/4/1960. The debate was planned for the day following three primaries, in which JFK ran unopposed in IN, a JFK-stand in ran unopposed in OH, and HHH faced Wayne Morse in DC. [NYT 4/23/1960]

A complication in the plans occurred on 4/28/1960 when CBS announced that it would not carry the debate because not all Democratic contenders were invited. This had been a constant problem in previous attempt to organize debates. ABC offered to have the two candidates on its talk show "Open Hearing" instead of televising the debate, but NBC took the initiative by asking if it could carry the debate on its television network. [NYT 4/29/1960]

The two candidates agreed on most domestic and foreign policy issues. They identified two issues on which they disagreed. HHH favored an increase in income tax exemptions from $600 to $800 to assist lower income groups, which JFK opposed. HHH also wanted a national fair trade law, which JFK believed would set off inflation. Both agreed that a Nixon presidency would be bad for the nation and would constitute a third Ike term. They also agreed that religion should not play a role in the primary or general election. Neither wanted Communist China to be admitted to the UN and wanted to shift foreign aid to economic development loans.

A major current of the debate involved the issue of "ganging up" on candidates. HHH charged that thousands of Republicans voted for JFK in Wisconsin and that JFK's supporters actively worked for Morse in DC. JFK stated that HHH had formed a coalition in WV with supporters of Johnson and Symington in order to stop his campaign. When JFK stated that the primary in WV was critical, HHH retorted that it was hardly the "Alpha and Omega, the beginning and the end" of the campaign.

One minor way in which JFK stood out was his attempt to show how he would pay for the programs he proposed. [NYT 5/6/1960]

The final question to each candidate was who won the debate (every debate deserves one childish question). HHH believed that the Democrats won. "The Republicans lost." JFK said "We'll know next Tuesday." [NYT 5/5/1960]

Aftermath
The immediate response was that JFK outperformed HHH. James Reston wrote for the NYT that JFK "made a more vivid and effective presentation of his case... It was Senator Kennedy who concentrated on the local issues, who presented the specific illustrations, and who avoided the jargon of Washington for the simple language of the average voter." [NYT 5/5/1960].

HHH disagreed with conventional wisdom. He said that the debate was good for the state and the party and was bad for the Republican Party. Leading Republicans asked for equal time but were denied it on the basis they did not have a contested nomination. [NYT 5/6/1960]

Regardless of HHH's claims, JFK was the clear winner. A poll in Fayette County showed that HHH's support dropped from 60% to 37% following the debate. [NYT 5/6/1960]

Republican leaders appeared on the Mutual Broadcasting Network on the evening preceding the primary. They maintained that the JFK-HHH debate was actually an anti-DDE campaign event. Gov. Cecil Underwood and Sen. Thruston B. Morton gave the Republican rebuttal. Underwood said that it was the first debate he had witnessed in which "the participants used their rebuttal to second what the other said." [NYT 5/10/1960]

The result of the primary confirmed the debate. JFK won a dramatic 61-39% victory. He won 48 of the 55 counties, and soon afterwards HHH withdrew from the race.